Can anyone guess why this didn't work?

I have been making yogurt fine for some time now. Got a powdered culture I keep in the freezer and use about 1/64 teaspoon worth per liter of milk. But its only two cultures.

So I saw these capsules - https://www.blackmores.com.au/products/probiotics-daily-health - 5 strains. Could these make yogurt I asked myself. I used a whole capsule for 1L with 75g of milk powder. This is about 6 times more volume than my usual culture powder.

Didn't set after 8 hours at a constant 40deg. Small, but very few clumps of solids clinging to the jars, the rest is pure liquid. Slight smell of yogurt. Ph test strip says about 5.3. My normal culture produced a ~4.3 only 24 hours before.

Maybe these strains are just not suited for growth in milk? Or do they have a cold temp preference? But how would that work inside the stomach? Not enough bacterial count?

Any ideas?